Euphorbia Trigona Rubra

Euphorbia Trigona Rubra Image

Euphorbia Trigona Rubra originates from Central Africa in the nations of Gabon, Malawi, Angola, and the Central African Republic. These areas are covered with tropical forests, so you will likely find this plant in these forests. Euphorbia Trigona Rubra is a variant of Euphorbia Trigona. The main difference between Rubra and the regular Euphorbia trigona is the pigmentation of the stem and the leaves. Regular Trigona has a green pigmentation on all its surfaces, but Rubra has a purple-red color on the leaves and stem. Some of them have a bronzish color.

  • Sunlight: bright but doesn’t get scorched by the sun.
  • Watering: enough water will sustain the plant.
  • Temperature: does well in arid climates, often characterized by high temperatures.
  • Soil: well-draining soil is vital.
  • Growth Season: Spring/Summer.
  • Propagation: Easily propagated from stem cuttings and seeds.

Names of Euphorbia Trigona Rubra

This plant has several common names shared across the species. Thus they are also the common names used for regular Euphorbia Trigona. They include the African Milk Tree, Friendship Cactus, Cathedral Cactus, etc.

Is Euphorbia Trigona Rubra Succulent or Cactus?

As you can see from the common names above, many people consider the African Milk Tree as a cactus. Indeed there are many similarities between it and the cactus. The thorns, the shallow root system, and a succulent stem are cases. However, the plant isn’t a cactus. It is succulent.

The genus Euphorbia, to which the African Milk Plant belongs, is one of the most diverse plants in the world. It has over 2100 species. Plants under this category have specific shared characteristics. Check out some euphorbia cactus species.

Morphological Characteristics

The African Milk Plant produces a milky sap that, when injured. The fluid, known as lumber, is standard among all euphorbia species. The milky juice is toxic, making the plant unpalatable to pests and harmful to children and pets.

#1. Spikes

Euphorbia Trigona Rubra also has spikes, another common characteristic of euphorbia. The African milk tree has spines on the stem, and every leaf that grows corresponds with a thorn. This is a big plant that can attain a height of nine feet. However, you can manage its size and keep it small, especially if you want to keep the plant in the house.

This plant’s trunk is triangular, and the spines grow where two parts of the triangle intersect. The African Milk Plant, therefore, appears like a triangle in 3D. We mentioned earlier that the leaves appear alongside the spines, giving the plant’s angular sides an even more fantastic appearance.

It is an excellent plant for a hedge when grown outside due to its height and how fast it grows. It can grow up to two feet per year which is remarkable. The root system of this plant is relatively shallow, and it is somewhat mismatched with the large, heavy trunk. Surface roots are why old Euphorbia trigona rubrics fall when they get old.

#2. Flowers

Euphorbia Trigona Rubra produces flowers. These flowers are usually white, and they come in clusters of male and female, where several male flowers surround one female flower. These flowers only bloom when the plant is consistently exposed to sunlight for four hours daily. It follows, therefore that plants grown indoors seldom bloom. In theory, plants grown outdoors can bloom at any time of the year, but they only bloom in spring and summer. These are the two-season when there is adequate sunlight to facilitate flowering.

euphorbia trigona rubra with reddish leaves
Photo by @gamm_vert via Pinterest

Euphorbia Trigona Rubra Care

#1. Light

While this plant grows in tropical Africa, it doesn’t do well under direct sunlight. Therefore, you should ensure the light is bright but doesn’t get scorched by the sun, at least not entirely. Sunlight is so vital to this succulent that it doesn’t flower unless it grows outdoors where the sun is abundant. If you are planting it indoors, you can keep it near a window that allows sunlight to come directly to your plant.

The morning sun is alright in most cases. Place the plant behind a sheer curtain if you are experiencing a sweltering summer to keep it from getting scorched. You can intensify the light by painting the room in light colors which reflect the light and feed the plant more intensively. In the seasons when the sunlight is too weak, like winter, you can move the plant outside to enjoy the little sunlight available.

On the other hand, if your Euphorbia Trigona Rubra is growing outdoors, grow it under a canopy of trees or provide shade for it in some other way. You could also plant it in a pot and move it to where the sun isn’t too hot in scorching summer.   

#2. Soil

The ground on which you plant this succulent needs to be well-drained. If it has too much clay, the roots will stay in a wet environment, leading them to rot. Therefore, if you are planting in a pot, buy cactus mix and then add gravel to it to make it easier to drain.

If you want to grow it outside, ensure the soil drains quickly. You can mix loamy with stone for the same reason. It is possible to enhance the soil’s drainage by building French drains if you have planted the Euphorbia trigona Rubra outdoors on clay soil. The soil type itself is not a factor as long as it is well-drained. Soil pH is not too much factor; the plant can do well in basic and acidic soils.

#3. Water

When discussing the soil, well-draining soil is vital because too much water is the greatest threat to the plant since it causes root rot. A trigona Rubra plant that grows outdoors doesn’t need to give it extra water if it is well established. The rainwater and humidity in the atmosphere are enough to sustain it. This is the standard position; unless you are experiencing an uncommon, long-term drought in your area, you might need to water the plant.

It would help if you gave the plant a moderate drink once in a while when practicing house culture. How do you know it is time to water your Euphorbia trigona Rubra? The answer to this is simple enough; you only water the plant when the plant has utterly exhausted water from the previous drink.

You determine if the soil is dry enough by dipping your fingers into the first two inches of the soil. Avoid watering if you encounter moisture at any point within two inches. Water from the previous drink has not been exhausted. On the other hand, if you find the soil dry, allow it time to water.

Checking the plant on a moment-by-moment basis is the best approach because temperature levels are not the same in different places, even in the same seasons. Thus while we can predict your plant will need more water in summer than in winter, the summer in your area may be hotter than in other locations, and one summer might be different from the next.

#4. Humidity

Euphorbia trigona Rubra is adapted for hot, dry environments. It doesn’t require too much humidity and can survive in dry areas. Too much moisture can make the plant vulnerable to fungal infections such as cork disease. Some pests may find the humidity conducive for breeding, thus affecting the plant negatively.

#5. Fertilizer

The African Milk Plant is hardy, and it doesn’t need too much additional feeding. How much you feed depends on the season. Please give it a little fertilizer in spring and summer, its growing seasons, and leave it unfed for the rest of the year. You should give it a water-soluble fertilizer that has been mixed to half-strength and only once a month. Avoid fertilizers with boron as many euphorbia plants react badly to it.

#6. Temperature

Temperature is not a big problem for this plant as it is drought resistant. It does well in arid climates, often characterized by high temperatures. The only safeguard you might need to make in this regard is if you live in a place with hot sun.

It is advisable to protect the plant from direct sunlight by providing partial coverage from the sun. Euphorbia trigona Rubra is not cold hardy. Plant it indoors if your area experiences freezing winters. Plant it outdoors in an area with frigid winters, plant it in a pot and move it indoors where the house will protect it in winter.


Euphorbia trigona, like other plants in the genus, can survive a fantastic amount of pruning. You can cut off up to 75% of the shoot, and it would bounce back. Pruning is an essential part of this plant’s husbandry.

It has a shallow root system, yet, as we saw earlier, it grows up to nine feet tall, and its trunk is water storage, which means a high center of gravity and weight. This combination is why old African Milk Plants tend to topple over. It would help if you pruned it to reduce weight on the plant’s upper body to reduce pressure on the roots.

It is also vital to ensure you prune it evenly on all sides. Else, there will be too much weight on one side that can cause the plant to keel over. When pruning, please remember the sap produced by this plant is toxic, and wear the appropriate protective clothing.  


There are two ways of propagating euphorbia seeds and stem cuttings.

Propagation by Stem Cuttings

It would help if you had the following things, so put them together before starting.

  1. A sharp cutting tool such as a knife or hand pruner
  2. Alcohol wipes, methylated or surgical spirit, and cotton wool
  3.  Four-inch pots depending on the number of plants you want to propagate
  4. Cactus mix and coarse gravel
  5. Heavy gloves and goggles

Take the following steps for successful propagation:

  1. Put on your gloves and goggles to protect your skin and eyes from the toxic milky sap that will run from the plant.
  2. Take your cutting tool, whether a knife or pruner and wipe it with alcohol wipes. If you don’t have alcohol wipes, dip a piece of cotton wool into the spirit and swab the cutting tool with it. Sterilizing the instrument is an integral part of the process as it ensures neither the daughter nor mother plant gets infected with any disease that might be on the tool.
  3. The plant has branches referred to as arms. With your now sterilized tool, cut one arm at the base. The plant and the component will start oozing sap. Rinse the cutting with cold water to stop it from bleeding. Cold water causes the fluid to thicken fast. You can also spray the mother plant’s injury with cold water to keep it from oozing.
  4. Allow the cutting to dry off by keeping it under a shade for seven days. Please note that the cutting would still root if you planted it without allowing it to callus. However, the cutting will be susceptible to rotting.
  5. Put your potting mix into one of the pots, plant your cutting in it, and add some gravel on the top to keep the cutting stable. The additional support from stone is necessary because you shouldn’t bury the cutting more than one inch below the ground.
  6. Water the cutting and put the pot away from direct sunlight, within a temperature range between 65 and 75oF. This cutting should root within eight weeks. Water it regularly to keep it growing.
  7. Transplant it into a bigger pot when it roots. Remember you embed it in a 4-inch pot, so you should move it to a pot at least 6 inches wide.

Note: If you want to grow the cutting outdoors, you can root the cutting in the permanent position where you want the plant to grow. Only be sure to provide it with the conditions described above.

Propagation by Seed

It is possible to propagate the African Milk Tree using seeds, but it is difficult, and its outcome is uncertain. First, it is difficult to get the roots, and when you find them, you will find it difficult to break their dominance. If, however you see the seeds, put them in a potting mix similar to the one you use in cuttings. Water it and keep it under the shade where the temperature is between 65oF and 75oF.


The African Milk Tree grows relatively fast, as we have seen. You will need to repot it from time to time for optimum performance. How can you tell your Euphorbia trigona Rubra is underpotted? Answering this question is the first step, as it allows you to determine whether potting is necessary.

You need to repot if you see roots protruding from the pot’s drainage holes. It is also necessary for you to repot your plant when you find that the stems are growing too tall and heavy for the pot in which you have planted them to support their weight sufficiently.

Spring and summer, the plant’s growing season, is the best time to repot the plant. The timing is appropriate because your Euphorbia trigona Rubra will grow immediately after repotting and cure any injuries it may have sustained when repotting.

It would help if you had the following:

  1. Cactus mix
  2. Pumice or perlite
  3. Compost
  4. Knife
  5. Twine
  6. Gloves
  7. Goggles
  8. Bigger pot


  1. Put on protective gear (goggles and gloves)
  2. Tie the various stems of the Euphorbia trigona Rubra together at different points to make them easier to handle.
  3. Take the knife and run it along the pot’s circumference. This helps you to loosen the root ball.
  4. Lay the plant on its side and pull the plant out. The soil on which the succulent is planted is usually loose, and it should be easy to remove the plant.
  5. Take the new pot and cover its drainage holes with cactus newspaper, coffee filter, or light paper to prevent the potting mix from escaping through it. The cover should be permeable enough to allow water to pass through as necessary. 
  6. Fill the pot partway with the cactus mix and pumice on a 50:50 ratio, add some compost, and mix. You should put just enough to ensure when you place the root bulb in, it will fit nicely in the pot.
  7. Fill in the remaining space in the pot with the remaining potting mix and press it down.
  8. Water it and place it in a suitable location with lots of light.

Pests and Diseases

The toxic sap in this plant makes it unpalatable for most pests. Mealybugs and plant scale are, however, still a problem. You can tell your plant is infested when you see your otherwise bright green plant develop white threads that look like cotton. Mix some water with a mild detergent and spray the infected parts of the plant. You can also remove the bugs by rubbing alcohol on the infected legs. You can dislodge the bugs by spraying them with water under high pressure.

The plant scale is as hardy as mealybugs. Their control is made difficult by the covering shell they have and the fact that their females lay hundreds of eggs, and they can make the pest challenging to manage when they hatch.

Fungal diseases such as cork disease infect the plant due to overwatering. It is also possible to have the plant suffer from root rot. Cut off the infected parts if your Euphorbia trigona has the cork plant. Yellowing leaves often indicate overwatering, and they can get back to color if you reduce the water. This plant’s leaves are the most delicate and are the best indicator of its health.


In conclusion, this beautiful plant requires pretty normal conditions. It is also relatively easy to care for; you should be most wary of the possibility of toppling over due to its shallow root system if it grows to its full stature. Constant and careful pruning should keep this from happening. Your Euphorbia Trigona Rubra will be as perfect as it can be.

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Succulent City chief editor


Succulent City

Hey everyone! Welcome to Succulent City! We are all about succulents, cacti, and a bit about air plants. Ten years back, in 2013, we began the journey with succulents. It started as a simple hobby, crafting and selling charming succulent-themed pins and decorations. But as time passed, our fascination with these remarkable plants grew, and we gained extensive knowledge about them. Therefore, Succulent City is the blog as you see it is now. Enjoy your visit and happly planting!

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